原发性肺癌GSTM1基因多态性与化疗效果关系的研究靠

背景与目的GSTM1参与环境污染物如苯丙芘和其它多环芳烃及抗癌药等的代谢,其多态性是否会影响肺癌患者的化疗效果及预后,国内相关研究比较少,本研究旨在揭示GSTM1多态性是否与化学药物治疗的敏感性有关以及对患者预后的影响。方法采用聚合酶链反应技术,检测接受化学药物治疗的137例原发性肺癌患者GSTM1基因型频率分布情况。结果137例肺癌患者GSTM1缺陷型频率为58.4%(80/ 137),功能型频率为41.6%(57/137);化疗有效组GSTM1缺陷型频率为69.05%(58/84),化疗无效组GSTM1缺陷型频率为41.51%(22/53),二者有统计学差异(P=0.001)。采用铂类化疗方案的患者,化疗有效组GSTM1缺陷型频率为65.43%(53/81),化疗无效组GSTM1缺陷型频率为42%(21/50),二者有统计学差异(P= 0.0025)。对于进展期患者化疗有效组GSTM1缺陷型频率为70.13%(54/77),化疗无效组GSTM1缺陷型频率为41.51%(22/53),二者有统计学差异(P=0.001)。当化疗有效时携带GSTM1功能型的鳞癌、小细胞癌患者生存时间(中位生存期分别为42个月和14个月)比携带GSTM1缺陷型的鳞癌、小细胞癌患者长(中位生存期分别为6个月和7个月)(P<0.05);而腺癌患者,携带GSTM1功能型和缺陷型的生存时间(中位生存期分别为13个月和11个月)差异无统计学意义(P>0.05)。对于化疗无效的患者,不论GSTM1为何种基因型、病理分型如何,患者中位生存期均比较接近,生存时间没有统计学差异(P>0.05)。结论GSTM1缺陷型的患者接受化学药物治疗的效果比GSTM1功能型的患者好;采用铂类化疗方案时GSTM1缺陷型的患者化疗效果比GSTM1功能型的患者好。当化疗有效时,患者生存时间与病理分型、GSTM1基因型相关。     

高山红景天提取物对糖尿病大鼠谷胱甘肽过氧化物酶活性及丙二醛含量的影响

目的观察高山红景天提取物对链脲佐菌素(STN)诱导的糖尿病大鼠肝组织中的谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)活性及丙二醛(malodialdehyde,MDA)含量的影响。方法采用链脲佐菌素诱导糖尿病大鼠模型,分别测定各组大鼠使用高山红景天提取物处理前后大鼠肝组织中GSH-Px活性和MDA含量。结果高山红景天提取物可提高糖尿病大鼠肝组织中的GSH-Px活性,降低MDA含量。结论高山红景天提取物对糖尿病大鼠具有清除自由基及抗脂质过氧化作用。     

依达拉奉治疗急性脑梗死的临床研究

目的:研究依达拉奉治疗脑梗死时对丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)的影响及疗效.方法:入选200例患者,随机分为依达拉奉组105例、对照组95例,在治疗前、治疗后第4、7、11、15天采静脉血测定MDA、SOD、GSH-Px浓度,并进行治疗前、后ESS评定.结果:与治疗前相比,治疗后第11、15天按欧洲神经功能缺损评分量表(ESS)衡量明显增高,(P＜0.01).治疗后第4、7、11、15天,MDA较治疗前降低,(P＜0.01);SOD、GSH-Px较治疗前升高,(P＜0.01).在第15天时,三者处于稳定状态.结论:依达拉奉降低MDA,升高SOD、GSH-Px,清除自由基,保护脑细胞,有助于降低脑梗死致残率.     

Effects of trichlorfon on malondialdehyde and antioxidant system in human erythrocytes

Organophosphorus insecticides may induce oxidative stress leading to generation of free radicals and alteration in antioxidant system. The aim of this study was to examine the potency of trichlorfon, an organophosphate insecticide, to induce oxidative stress response in human erythrocytes in vitro. For this purpose trichlorfon solutions in different concentrations and erythrocyte solutions were incubated at 37 °C for 60 min. At the end of the incubation time, malondialdehyde (MDA), an end product of lipid peroxidation, total glutathione, reduced glutathione (GSH) levels, activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) enzymes were determined by spectrophotometric methods. Trichlorfon increased MDA formation depended on the concentration. On the other hand, decreases in the GSH-Px activity, GSH levels and increases in the total glutathione levels, SOD and CAT activities were seen in the studied concentrations. The present findings indicate that the in vitro toxicity of trichlorfon may be associated with oxidative stress.     

乳腺癌组织中多药耐药相关基因产物的表达及其相互关系

目的探讨多药耐药（MDR）基因产物P-糖蛋白（P—gp）、谷胱甘肽-S-转移酶-π（GST-π）及DNA拓扑异构酶Ⅱ（TopoII）在乳腺癌组织中的表达及其相互关系。方法采用免疫组织化学方法，检测184例未经抗肿瘤治疗的原发性乳腺癌组织中P—gP、GST-π及Topo II表达水平。结果乳腺癌组织中P—gP、GST-π和TopoII阳性表达率分别为49．51％、45．65％和73．91％，TopoII阳性表达率明显高于P—gp及GST-π阳性表达率（P〈0．05）；2种多药耐药基因产物共表达率为30．98％，2种和3种多药耐药基因产物共表达率为67．39％，明显高于单独表达率12．41％（P〈0．01）；P—gP与GST-π的表达呈显著正相关（P〈0．05），P—gP和TopoII的表达呈明显负相关（P〈0．05），GST-π和TopoII的表达呈明显负相关（P〈0．05）。结论P—gP、GST-π及TopoII在乳腺癌组织中表达对肿瘤耐药起重要作用，单基因和多基因协同作用，以多基因共表达为主。     

Homozygous gene deletions of the glutathione S-transferases M1 and T1 are associated with thimerosal sensitization

Objective: Thimerosal is an important preservative in vaccines and ophthalmologic preparations. The substance is known to be a type IV sensitizing agent. High sensitization rates were observed in contact-allergic patients and in health care workers who had been exposed to thimerosal-preserved vaccines. There is evidence for the involvement of the glutathione system in the metabolism of thimerosal or its decomposition products (organomercury alkyl compounds). Thus detoxification by polymorphically expressed glutathione S-transferases such as GSTT1 and GSTM1 might have a protective effect against sensitization by these substances. Methods: To address this question, a case control study was conducted, including 91 Central European individuals with a positive patch-test reaction to thimerosal. This population was compared with 169 healthy controls and additionally with 114 individuals affected by an allergy against para-substituted aryl compounds. The latter population was included in order to test whether possible associations were due to substance-specific effects, or were a general feature connected with type IV immunological diseases. Homozygous deletions of GSTT1 and GSTM1 were determined by polymerase chain reaction. Results: Glutathione S-transferase M1 deficiency was significantly more frequent among patients sensitized to thimerosal (65.9%, P=0.013) compared with the healthy control group (49.1%) and the “para-compound” group (48%, P=0.034). Glutathione S-transferase T1 deficiency in the thimerosal/mercury group (19.8%) was barely elevated versus healthy controls (16.0%) and the “para-compound” group (14.0%). The combined deletion (GSTT1−/GSTM1−) was markedly more frequent among thimerosal-sensitized patients than in healthy controls (17.6% vs. 6.5%, P=0.0093) and in the “para-compound” group (17.6% vs. 6.1%, P=0.014), revealing a synergistic effect of these enzyme deficiencies (healthy controls vs. thimerosal GSTM1 negative individuals, OR=2.0 [CI=1.2–3.4], GSTT1−, OR=1.2 [CI=0.70–2.1], GSTM1/T1−, OR=3.1 [CI=1.4–6.5]). Conclusions: Since the glutathione-dependent system was repeatedly shown to be involved in the metabolism of thimerosal decomposition products, the observed association may be of functional relevance. Received: 8 September 1999 / Accepted: 25 March 2000     

Intracellular glutathione and cytotoxicity of platinum complexes

Although there have been a number of reports correlating cellular GSH levels with cytotoxicity of platinum agents, none has examined the relationship between GSH concentrations and cytotoxicity. In this study, using a highly specific HPLC method for measuring GSH and expressing GSH as concentration and also per cell number, we evaluated the correlation between GSH levels and the cytotoxicity to five agents in ten human tumor cell lines. The five platinum agents included the platinum(II) complexes cisplatin, carboplatin and oxaliplatin and platinum(IV) complexes iproplatin and tetraplatin. The correlation between intracellular GSH concentration and cytotoxicity was highly significant only for iproplatin (P=0.002) followed by tetraplatin, which demonstrated a trend toward statistical significance (P=0.06). Cytotoxicity of the other platinum complexes showed no relation to GSH concentration, cisplatin itself showing aP-value of 0.09. In contrast, the GSH levels normalized to cell number showed a statistically significant correlation with the cytotoxicity of four of the five platinum agents, the exception being carboplatin; the strongest correlation observed was that for iproplatin and tetraplatin. Glutathione-S-transferase (GST) activity in these cell lines showed no correlation with cytotoxicity of any of the platinum complexes. Our results, from the analyses of both GSH concentration as well as GSH per cell number, suggest a significantly higher interaction between GSH and iproplatin compared with the other platinum agents. Moreover, our data suggest that relationships between cytotoxicity and GSH levels on a per-cell basis may not persist when differences in cell volume are taken into account.     

Expression of resistance-related proteins in tumoral and peritumoral tissues of patients with lung cancer

Twenty tumoral and peritumoral tissues from patients with lung cancer were analyzed immunohistochemically for the drug resistance-related proteins P-glycoprotein (P-170), topoisomerase II (Topo-II), glutathione S-transferase-π (GST-π), metallothionein (MT), heat shock protein-70 (HSP-70) and the putative regulators of resistance (ErbB1, Fos and Jun). Protein expression of Topo-II, GST-π, MT, HSP-70, ErbB1, Fos and Jun was elevated in tumor tissue in comparison to normal tissue. The different expression of the proteins between tumoral and normal tissues was statistically significant for Topo-II (P = 0.05), MT (P = 0.03), and HSP-70 (P = 0.01), whereas ErbB1 showed a borderline significance. The expression of the proteins was frequently increased in smokers in comparison to non-smokers. In general, the increase of the proteins of smokers corresponded in tumoral and non-tumoral tissue. Different expression was only found with MT and HSP-70 which were higher in tissues of smokers.     

Thiolic antioxidants protect from nitric oxide-induced toxicity in fetal midbrain cultures

Nitric oxide (NO) may act as a neuroprotector or neurotoxic agent in dopamine neurons, depending on cell redox status. We have investigated the effect of several thiolic antioxidants, glutathione (GSH), its cell permeable analog GSH ethyl ester (GSHEE), and the GSH synthesis precursor L-N-acetyl cysteine (L-NAC), as well as non-thiolic antioxidants like ascorbic acid (AA) and uric acid, on NO-induced toxicity in fetal midbrain cultures. The cultures were treated for 8-24 h with neurotoxic doses of the NO donor diethylamine/nitric oxide complex sodium DEA/NO (200-400 micro M) and/or antioxidants. Thiolic antioxidants, at equimolar concentrations, added at the same time or previous to DEA/NO, protected from cell death, from tyrosine hydroxylase (TH) positive cell number decrease and from intracellular GSH depletion, induced by DEA/NO, without increasing intracellular GSH content. In these conditions, S-nitrosothiol compound formation was detected in the culture media. Protection disappeared when antioxidants were supplied 30 min after NO treatment. Nevertheless, non-thiolic antioxidants, AA and uric acid, with similar peroxynitrite scavenging activity to thiolic antioxidants, and free radical-scavenging enzymes as catalase and Cu/Zn-superoxide dismutase, which prevent extracellular peroxynitrite ion formation, and 4,5-dihydroxy-1,3-benzene-disulfonic acid (Tiron), which prevents intracellular peroxynitrite ion formation, did not rescue cell cultures from neurotoxicity induced by NO. In addition, AA exacerbated DEA/NO-induced toxicity in a dose-dependent manner from 200 micro M AA. The present results suggest that only antioxidants with thiol group exert neuroprotection from NO-induced toxicity in fetal midbrain cultures, probably by direct interaction of NO and thiol groups, resulting in NO blocking. On the other hand, some classical antioxidants, like AA, exacerbate neurotoxicity due to NO.     

Antioxidant properties of MDL and MMDL,two nicergoline metabolites,during chronic administration of haloperidol

We evaluated the effects of 10-alpha-methoxy-9,10-dihydrolysergol (MDL) and 1-methyl-10-alpha-methoxy-9,10-dihydrolysergol (MMDL), two nicergoline metabolites, during chronic treatment with haloperidol in rats. Haloperidol induced a significant decrease in the glutathione (GSH) content in selected areas of the brain and in the liver. Prolonged administration of MDL, MMDL or nicergoline antagonized the haloperidol-induced GSH decrease. Lipid peroxidation in the cortex and striatum was suppressed by MDL, MMDL or nicergoline administration. Our results show that MDL, MMDL and nicergoline have antioxidant activity, preventing not only GSH depletion but also lipid peroxidation. These observations suggest beneficial properties of MDL and MMDL in the treatment of neuroleptic-induced side effects.